Air circulating system for mobile dispensing freezers



ly 0, 1965 H. F. SWENSON 3,195,522

AIR (JIRCULATING SYSTEM FOR MOBILE DISPENSING FREEZERS Fild Feb. 21, 1963 2 Sheets-Sheet 1 HARVEY F. SWENSON INVENTOR.

ATTORNEYS July 20, 1965 H. F. SWENSON AIR CIRCULATING SYSTEM FOR MOBILE DISPENSING FREEZERS Filed Feb. 21, 1963 2 Sheets-Sheet 2 lllllllllllll .l HHHI HHHH I I HUU w N Ill lwhllllllllll. F-IIl-rllll llllll .ll lllll ll I|.r.|

R 0 sm Nm 2 m m W F M m Y E V m H m 1 United States Patent Ofi ice 3,195,522 Patented July 20, 1965 3,195,522 AIR CIRCULATING SYSTEM FOR MOBILE DISPENSING FREEZERS Harvey F. Swanson, Seattle, Wash assignor to Sweden Freezer Manufacturing (30., a corporation of Washington Filed Feb. 21, 1963, Ser. No. 260,129 2 Claims. (Cl. 123-4155) This invention relates to dispensing freezers in which the dasher for the freezing cylinder and the compressor in the refrigeration system therefor are both driven by an internal combustion engine, such for example as shown in Us. Patent No. 3,052,103. More particularly, the invention concerns an improved air circulation system aiming to provide more effective and efficient cooling for the refrigeration system components and the engine of such a mobile dispensing freezer in a simple and economical manner.

In carrying out the invention an air cooled engine is provided of the type having a blower for circulating cooling air over the engine, and a fan driven by the engine is arranged to circulate airthrough the condenser component of the refrigeration system for the freezer. The invention aims to utilize the blower and fan in an improved arrangement and manner whereby they complement one another for greater output and whereby the cooling needs of the refrigeration condenser and compressor together with those of the engine are efficiently satisfied with varying loads.

A further object is to provide such cooling while at the same time giving easy access to the engine and refrigeration system.

These and other objects and advantages in view will appear and be understood in the course of the following description and claims, the invention consisting in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

7 back by swinging doors 1415 hinged to the rear of the side walls Ida-13b, respectively, and the front of the com partment is closed by a bulkhead 16 above which the dispensing freezer and usual related equipment are mounted. This equipment juts rearwardly of the bulkhead 16 so that the base and back wall 16a thereof complement the roof 12 and bulkhead 16 in closing the front and top of the compartment 10.

Power for the freezing and dispensing apparatus is supplied by an air cooled internal combustion engine 19 mounted on the floor 11 proximate the left door 14. This engine turns a main drive shaft 17 through a suitable belt and pulley drive 18. Mounted on this main shaft 17 are three drive pulleys 20, 21 and 22 by which power is transmitted through respective belts 23, 24 and 25. The pulley 20 with its belts 23 turns a pulley 26 fixed to a shaft 27 which drives a refrigerant compressor 28 and a fan 30 located on the right side of the compartment 11 This compressor is arranged in a conventional refrigeration circuit with the freezing cylinder 8 and a condenser 31 as disclosed in the aforementioned patent. The fan 30 is designed to draw atmospheric air from outside the vehicle body for circulation through both the condenser and engine before being discharged back outside. The manner in which this is accomplished is of particular importance in the present invention and will be described more fully hereinafter.

The main drive shaft 17 may turn a small generator (not shown) or other auxiliary unit through the pulley 21 and belt 24, and by pulley 22 and belt 25 periodically passes power upwardly to a pulley 21 onthe shaft 32 of a dasher functioning in the freezing cylinder 8 to beat the frozen product and urge it to a discharge gate at the front of the freezer for dispensing. This periodic transmission of power from shaft 17 to the dasher is accomplished by means of a speed responsive clutch 34 which functions to engage the pulley 22 only when the shaft 17 is rotating above a predetermined r.p.m. Thus when the engine 19 is operating below this predetermined speed the compressor 28 and fan 3i) are operating at a relatively low speed while the dasher is stationary.

In a days run, during those periods when no frozen product is being dispensed, the compressor is able under normal circumstances to circulate enough refrigerant through the freezing cylinder 8 to maintain the mix therein in a properly frozen condition while the engine is running in its lower speed range. But when the discharge gate of the freezer is opened to dispense frozen product from the freezing cylinder, a suitable control mechanism causes the engine to increase in speed to engage the clutch 34 and thereby drive the dasher shaft 32. At the same time the output of the compressor 28 andfan 39 are of course increased responsive to the increased speed of the engine. This same increase in engine rpm. also takes place in response to a rise in temperature of the mix above a predetermined level. The precise manner in which refrigerant is circulated and the engine is controlled is described more fully in the aforementioned patent and will not be enlarged upon herein. However, it is important to note that during these periods of increased motor speed, there is increased load on the motor not only from the compressor 28 and fan 30 operating at increased speed, but also from the dasher 32 coming into operation. Thus not only must the condenser 31 dissipate heat at an increased rate because of the increased flow of refrigerant but more heat must be conducted from the engine.

To accomplish its air cooling, the engine is provided with a centrifugal blower 36 mounted on the engine drive shaft adjacent the left rear door 14 and arranged to draw air over the head of the engine. The air outlet 37 of the blower is directed upwardly and opens at a location moderately in front of, and at the approximate vertical center line of the door 14. To cooperate with this outlet 37 there is mounted on the inside of the door 14 a vertical discharge duct 38-. When the door is closed the intake opening 40 of this duct is located adjacent to and immediately above the blower outlet 37. The duct outlet is formed as a screened opening 41 near the top of the door 14. It will be noted that the duct is tapered, being broadest at its intake, and that the area of the duct intake opening is purposely larger than that of the blower outlet 37. Thus the perimeters of these two openings define therebetween an eductor opening 44 which extends around the periphery of the blower outlet 37. Accordingly, as

. the blower draws air through the engine to cool the same and discharges this air through its outlet 37 and into the duct 38, the surrounding air within the compartment 11 is drawn thereby into the duct through the eductor opening 44 and is also discharged to the outside.

Proceeding now to a description of the inlet for the cooling air, it will be noted that the lower portion of the right rear door 15 is provided with a screened intake openingfifij which is, alined with the condenser 31 when the door is closedl The intake 46 and condenser are placed in direct communication by'a box-like inlet duct 47 defined by center and upper divider walls 48-49; respectively, together vwith the side wall'lfib and floor 1,1 When it is closed, the door; 15 sealss'o that air can only. enter through the opening46. Thus the fan 30 continu ously draws'air forward through the opening 46, the duct 47, and condenser 31 into the right' front portion offthej;

compartment 10. A portion of-this air isthen rectly by the blower 36 to the left and'rearwardly to the engine to be discharged'throughthe outlet37 and out the duct 38. The rest of the air circulates toward the eductor opening 44 and is drawn from the compartment by the eductive action of the air discharging from the blower into the discharge duct 38. Thus not only does the blower 36 serve its conventional engine cooling function, but it facilitates the total circulation of air by such eductor erreeton the rest of the air in thecompartment, and thereby complements the fan 30; It Willbd notedsth at the circulatingair not only cools the condenser and engine but also cools the compressor 28 and other apparatus in the compartment, 7 Since the aircooling requirements -increase when froien product is dispensed from the freezer,

i the system is unusually efficient because whenth'e engineautomatically speeds'up responsive to this condition, the

speed and output of theblower and fan are likewise inef creased. t a. t

It is believed that. the invention will have been clearly understood from-the foregoing detailed description of my now preferred illustrated embodiments. Chan es in the details of construction will suggest themselvesjand it is accordingly my intention that no limitations be implied and that th'e'hereto annexed claims be given the broadest interpretation to which the employedlanguage fa'irly ad-' What I claim is:

-1. In,combination, a motor truck shaving aacompart- I mentswith an outside access door, said compartment having an air inlet and having an air outlet in said door, an 5 engine in said compartment, an engine-cooling blower driven by the engine and arranged to draw cooling air 'overfi the engine, atap'red discharge ductto said'outlet mounted on the door and having the mouth of its larger end surrounding the discharge ,end of said blower in educ'tor relationship 'When the door is closed for pulling air from saidcompartment in addition to that passing through the" blower. 7 1

2. In combination, a motor trnck having a compartment withtwo outside access doors an air inlet in one 1 5 'of'said doors and an air outletinthe other door, an en-- gine in said compartment, an engine-cooling blower driven by the engine and arranged to draw cooling air over. the engine, a tapered discharge duct to said outlet mounted on the respective door and having the mouth of its larger 20 end surrounding the dischargeend of said blower in educ't-or relationship when the dooris closed for pulling air fromasaidcom'partment in addition to that passing through the blower. i i l 5 References Cited ,bythe Ekaininer v UNITED STATES PATENTS -1 6 98,-122 1/ 29 Collins;, .l 62-456 1,922,079 3/33 Anderson 98-43 2,049,799 8/36 .;Cand01 62'45 5 2,513,679 7/50fRitter 62239 2,544,579; 3/51 Davenport 98,-43 "2 ,630,687 3/53 Act'on 62f'239' 3,052,103 V 9/62.

I 'Clark 62208 WILLIAM J. WYEfPrimary Examiner.

ROBERT A. OLEARY, Examiner. 

1. IN COMBINATION, A MOTOR TRUCK HAVING A COMPARTMENT WITH AN OUTSIDE ACCESS DOOR, SAID COMPARTMENT HAVING AN AIR INLET AND HAVING AN AIR OUTLET IN SAID DOOR, AN ENGINE IN SAID COMPARTMENT, AN ENGINE-COOLING BLOWER DRIVEN BY THE ENGINE AND ARRANGED TO DRAW COOLING AIR OVER THE ENGINE A TAPERED DISCHARGE DUCT TO SAID OUTLET MOUNTED ON THE DOOR AND HAVING THE MOUTH OF ITS LARGER END SURROUNDING THE DISCHARGE END OF SAID BLOWER IN 